Bibb County Glades
guest post by intern Ian Hazelhoff
On June 1, I was fortunate to attend the annual Bibb County Glades field trip for the Certificate in Native Plant Studies program. Fred Spicer and John Manion led the charge on a spectacularly overcast day prime for botanizing. Several other enthusiastic individuals, ranging from Master Gardeners to The Gardens’ Director of Library Services, Hope Long, filled in the ranks of our troop. Insect repellant was applied, wide-brimmed hats adjusted, and introductions were shared. In total, the fieldtrip itinerary listed three glade sites and concluded with a tour of the Cahaba River’s largest lily site. Ambitious and driven by a unanimous desire to see some of the nation’s rarest plant species in habitats as unique as separate planets, we entered the glades.
To comprehend fully how this beautiful suite of rare plants can exist in such obscurity takes an understanding of this unique landscape. The Bibb County Glades sit perched on small veins of a rock named Ketona dolomite, which possess higher concentrations of magnesium than more regionally common formations of limestone. Species that thrive in magnesium rich soils are prevalent. The glades are also an “ecotone” region, where full forest environments gradually transition to more open, grassy areas. Nestled within this gradient are species specialized to thrive with exposure to more light and wind. Without a complete tree canopy, the glades represent an assemblage of highly specialized succession species existing in near total isolation.
In areas with Ketona dolomite based substrate, magnesium and often aluminum levels are so high as to be toxic to many more common species found in the region. As a historical note, Fred Spicer pointed out that seams of Ketona dolomite were once found scattered throughout Jefferson County, AL, however, these were the first to be mined during Birmingham’s steel boom. Dolomitic limestone is a precursor material for steel production, and to think that it also supports the livelihood of some of the rarest plants on Earth! With visions of steel furnaces and open pit mines at the helm, I quickly became aware of the true importance and special nature of the Bibb County Glades.
As the fieldtrip came to a close, I found myself traveling the winding waterside road to see one of my home state’s secret treasures: Cahaba lilies blooming in their prime. Pockets of lilies, with proud green stalks and exuberant white flowers, dotted the river’s center. John Manion was quick to point out that the heaviness of the lily’s seed allows it to sink and become lodged between rocks on the river’s bed. Cool water, sand, and fields of aquatic botanical wonder - not bad for a day at the office.
To learn more about the Certificate in Native Plant Studies series, and to register for any of its core classes, electives or field trips online, visit www.bbgardens.org/plantstudies.
Photos: Beth Maynor Young